To me, it's quite clear: the target language would have forked from its base, creating of necessity an incompatible ecosystem (no one wants an improvement after

To me, it's quite clear: the target language would have forked from its base, creating of necessity an incompatible ecosystem (no one wants an improvement after which you still can still make the same old mistakes, and some mistakes are emedded in the C/C++ syntax), and we'd end up with something slightly worse than Rust, using somewhat more familiar tools.